1. Field of the Invention
The present invention relates to a wire-cut electrical discharge machine and more particularly to a wire-cut electrical discharge machine having a nozzle means or supply nozzle permitting improvement in the efficiency of feeding a current to a wire electrode and the efficiency of removing machining chips from the electrical discharge machining zone in a workpiece.
2. Description of the Prior Art
In general, wire-cut electrical discharge machines comprise: a table which is adapted to be movable in the directions of X and Y axes; for supporting a workpiece, a wire supply unit for continuously supplying a thin wire electrode to an electrical discharge machining zone; and a wire take-up unit for continuously taking up the wire electrode. The wire-cut electrical discharge machines carry out an electrical discharge machining of a workpiece while slightly moving the same along X and Y axes. More specifically, a minute gap is formed between the workpiece and the wire electrode supplied from the wire supply unit to the electrical discharge machining zone, and the wire electrode is fed with a current in the form of pulses, thereby causing electrical discharges which continuously take place between the wire electrode and the workpiece.
For increasing the removal rate in the wire-cut electrical discharge machines of this type, it is necessary to make a power-feed portion for feeding electrical pulses to the wire electrode as close to the electrical discharge machining zone as possible in order to efficiently feed the electrical pulses to the electrical discharge machining zone. In addition, it is necessary to cool the power-feed portion as much as possible in order to prevent the wire electrode from being burdened. Moreover, it is required to reliably remove minute machining chips and other products resulting from an electrical discharge machining from the electrical discharge machining zone in order to maintain the condition about the electrical discharge machining zone in an excellent state under predetermined conditions.
In the wire-cut electrical discharge machines, however, in order to effect a highly accurate machining by the use of a thin wire electrode, the wire electrode which is continuously moved must be highly accurately guided and held at a precise position. Consequently, in the conventional wire-cut electrical discharge machines, the wire electrode guiding/holding portion is located close to the electrical discharge machining zone, while the power-feed portion for feeding electrical pulses to the wire electrode is disadvantageously largely separate from the electrical discharge machining zone, resulting in a low power feed efficiency. Moreover, when the guiding/holding portion is close to the electrical discharge machining zone, the efficiency of supply of a machining fluid to the electrical discharge machining zone is unfavorably deteriorated.